Lubricating composition



United States Patent Ofi 3,098,041 Patented July 16, 1963 ice 3,098,041 LUBRICATING COR [POSITION James 0. Koehler, Parma Heights, Ohio, and Headlee Lamprey, Lcwiston, N.Y., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filed Nov. 20, 1961, Ser. No. 153,751 9 Claims. (Cl. 252-35) The invention relates to a lubricating composition containing an additive which acts as a pour point depressant and corrosion inhibitor and which also disperses gums and sludge formed during use.

Lubricating oils of mineral origin are limited in their utility by certain characteristics. Many lubricants which are otherwise satisfactory become too fluid when hot, or too viscous when cold. Other lubricants under certain conditions tend to decompose and produce sludge and gums along with various acidic products which corrode steel, copper, and other metals. A lubricant which will perform satisfactorily under a Wide range of service conditions has been found difficult to obtain.

Various types of organic compounds have been suggested and tried as additives in lubricants for improving the characteristics of the lubricants and for broadening the range of conditions under which they are useful. Some of these are effective in promoting cleanliness in engines and other devices, especially at high temperatures, but the same additives may be relatively ineffective at low temperature operation unless high concentrations of the additives are used.

Other additives have been used for depressing the pour point of the lubricant, thereby extending the range of conditions for satisfactory service. These additives, however, normally require the addition of an anti-oxidant to prevent the occurrence of oxidation reactions in the oils so modified.

Accordingly, the main object of the invention is to provide a lubricating composition containing an additive which not only improves its lubricating properties by dispersing gums and sludge, but also acts as a pour point depressant and corrosion inhibitor.

The invention achieves this object by the incorporation in a lubricating oil as a corrosion inhibitor, pour point depressant, and dispersant between about 0.1 and Weight percent of at least one organo-metallic compound selected from the acylates of tin, lead, and silicon and the aminoalcohol and polyhydric alcohol derivatives of tin, lead, zirconium, and silicon. More particularly, the com pounds whereby the object of the invention is attained comprise:

a. Acrylates having the formula:

OR x

wherein M represents silicon, tin, or lead; R is a short chain alkyl group having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; and x is a small number, preferably less than or equal to about 10. Compounds wherein R contains up to four carbon atoms, R contains up to 17 carbon atoms, and x is from 1 to 5, have been found particularly effective.

b. Aminoalcohol derivatives having the formula:

( Q[ z)z R ]4 (H0 CR wherein Q represents tin, lead, zirconium, or silicon; R is a short chain alkyl group having up to 10 carbon atoms; R represents hydrogen and short chain alkyl and hydroxyalkyl groups having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; y is a number from 0 to 3; z is a number from 1 to 5; and p is a number having a maximum value of 4-y. Particularly effective are those compounds wherein R and R contain up to 4 carbon atoms, R contains up to 17 carbon atoms, and p has a value of at least one, The salts of these compounds, i.e., where p is at least one, have exceptional dispersing ability.

c. Polyhydric alcohol derivatives having the formula:

wherein Q represents tin, lead, zirconium, or silicon; R is a short chain alkyl group having up to 10 carbon atoms; Z is a short chain acyclic polyvalent saturated hydrocarbon radical having up to it) carbon atoms; y is a number from O to 3; and v is a number from 1 to 3. Those compounds wherein R contains up to 4 carbon atoms and Z contains up to 8 carbon atoms are particularly effective.

The foregoing compounds, their properties, and the preparation thereof are described in US. Patent 2,989,412 which issued to us on June 20, 1961, and US. Patent 2,978,347 which issued to us on April 4, 1961.

The polymeric chain length of the acylates is not believed to be of critical importance as long as the compounds are soluble in the lubricating oil. The chain length of these compounds is afiected by the following factors during their preparation:

(1) Hearing.Generally the longer the heating cycle, the longer the chain.

(2) Warer.-The amount of water added to reaction mixture affects the chain length, in that the greater the quantity of water added, the longer the polymer. Too much water, however, results in cross linking, and in formation of insoluble products.

(3) Molar ratio of reactants.-If two moles of carboxylic acid are used per mole of orthoester in preparing the acylates, a longer chain polymer results whereas with only one mole of acid per mole of orthoester, a shorter chain polymer results.

In accordance with this invention, it has been found that the above compounds suspend carbon formed during the operation of internal combustion engines, and prevent carbon from depositing on the metal surface in the engine, as well as reduce the pour point and enhance the corrosion resistance of the oils in which they are incorporated.

The mineral oils of lubricating viscosity in which the additives of the invention are effective include petroleum lubricating oils and petroleum engine oils. Petroleum lubricating oils are those petroleum distillates and residues having a viscosity above 50 seconds Saybolt at F. used for lubrication within the range of spindle oils to cylinder stocks. Engine oils are petroleum lubricating oils of moderate viscosity having an overall range of specific gravity of from 0.84 to 0.95 (37 to 17 degrees A.P.I.) and normally used for the lubrication of exposed bearings of internal combustion and steam engines.

The suspending power of these new organo-metallic compounds was determined by preparing a series of carbon black suspension in (a) kerosene and (b) kerosene containing a small amount of water, and observing the suspensions after a four day period. The light hydrocarbon fluid, kerosene, was employed in these tests in place of the heavier, more viscous lubricating oils. The suspensions formed in kerosene are more unstable than those made with lubricating oils, and settling of the suspensions is much more rapid in kerosene. Consequently, by using kerosene the relative dispersant characteristics can be determined in a matter of a few days. Further tests on carbon-lubricating oil suspensions confirmed the data on the relative dispersant characteristics of these compounds observed in kerosene.

For controls in the dispersant tests five different commercially available barium petroleum sulfonate additives commonly employed as oil dispersants in high detergent oils were used. The test procedure and results follow.

A paste containing 20 percent carbon black in a white base oil was prepared by milling (Binney Smith Company) and Nujol on a three roll ink mill for three passes. For the test, three grams of this paste was introduced into a Waring Blendor with 70 ml. of kerosene or a solution of the additive in kerosene. The amount of additive employed was 1 part of additive per 99 parts of kerosene by weight. The blender was run for three minutes, the suspension was immediately poured into a 100 ml. graduate and observed after four days standing. In another case where water was used, 0.3 ml. of water was added after the three minute mix, and mixing was continued for another minute before pouring the sample for observation. The results of the dispersant test described are shown in Table I.

TABLE I Test Suspended after 4 No. Additive Used days-drywith 0.5%

None 50 50 Barium Ietronatc, Basic. 100 21 Barium Sulfon'itc, Alk, 7 100 30 Barium Dinonylnaphthalon 100 .5 Barium Sultanate, 3A, Alk 100 39 Barium Petronatc, Ncutr 33 32 Tricthanolaminc Oleate 5/0 45 8 Dietbyl-di-(triethanolamine)silicate-N, N-

lliolcate. 100 100 9- Dietbyl-di- (trietliunolarnine)-silicate eate 75 50 10 Butoxy Stearoxy lolystannut llll) 100 ll Butoxy Stearoxy Polysilicutv 100 100 All the barium sulfonates except the neutral barium petronate, and four of our materials, exhibited good suspending power in dry kerosene. However, when a small amount of water was added to the suspensions only the four non-aqueous surfactants retained their ability to keep the carbon in suspension. All the commercial barium sulfonates proved to be ineffective in suspending carbon in kerosene in the presence of Water. The fact the non-aqueous surfactants are insensitive to the presence of water shows that these compounds are superior to the usual oil detergents during engine operation, since water is normally present in the crank case of automobile engines.

The compounds of the invention, particularly the metallo-triethanolamine derivatives of silicon, tin and lead act as corrosion inhibitors for steel by reacting with the acid by-products of lubricant decomposition and present acidic attack on the metal surfaces. This effect was shown by the following steel corrosion test.

Compounds were tested by preparing solutions containing 1 part of additive to 99 parts of base oil. The base oil was Royal No. 39 manufactured by Standard Oil of Ohio. Steel specimens (1" x 2" x A) were made fnom cold finished carbon steel (A.S.T.M. designation A108). The sanded and degreased specimens were immersed in the inhibited oil solution for one-half hour and Superba carbon black then hung on a rack for an additional half hour in order to allow the excess oil to drain off them. The oil treated specimens were tested by hanging them in a constant temperature room at 140 F. and percent relative humidity. The specimens were observed daily for the appearance of rust and the time noted when rusting first occurred.

The results of this test are shown in Table II. All the data shown in the table are an average of six different tests.

TABLE II The Eficct of Various Additives on the Corrosion Inhibiting Properties of Oil on Steel Stored at F.

The data in Table II indicate that several of the compounds of the invention are excellent corrosion inhibitors under the mild conditions of this test. An A.S.T.M. test entitled Rust-Preventing Characteristics of Steam-Turbine Oil in the Presence of Water (A.S.T.M. designation 0665-54) was selected as the best bench scale test for ascertaining the effects of the surfactants as corrosion inhibitors in lubricating oil.

This test evaluates the ability of inhibited oils, including those used in gears, to aid in preventing the rusting of ferrous metal parts should water become mixed with the oil. Its method involves stirring a mixture of 300 ml. of the oil (Pure 200 vis., Intermediate VI neutral, manufactured by the Pure Oil Company) with 30 ml. of synthetic sea water. The oil phase contains the corrosion inhibitor. The water-oil mixture is stirred at a temperature of 140 F. with a cylindrical steel specimen immersed therein. The test specimen is examined after 24 hours for the appearance of rust. If rust is observed, the oil fails the test. All tests were run in duplicate. Test results on some commercial oils are shown in Table III following.

TABLE III Rust-Preventing Characteristics of Some Commercial Lubricating Oils in the Presence of Sea Water Oil Results Pure Lube (Pure Oil Company) Passed. Shell X-lOU {Shell Oil Company). Do. Konlmotor 5D (City Service).... a Do. Simone ll-IJ (Sun Oil Company) Do. lreinex (Sohio) Do.

Atlantic (Atlantic on Company)... D0. lerrnulube (American Oil Company) Failed (Slight Rust). Quaker State tlcmi Refining Company) Failed (Very Rusty).

In order to make this test more stringent, a 1 percent acetic acid solution was substituted for the sea water and repeated the above test. The data are shown in Table V.

TABLE V The Rust-Preventive Characteristics of Inhibited Oil in the Presence of 0.5% Acetic Acid Additive Cone, Results percent Barium Petronate, 3A, Alkaline 1 No Rust. Dibutyl-dHtriethanoiamine)-silicate-N,N- 1 Do.

dioleate. Diethyl-di-(fl-dicthyianzino) ethyl-silicate- 1 D0.

N ,I dialects. Barium Dinonyinaphthalcne Suifonate I Rusty. Barium Sulionato, Alkaline 1 No Rust. Barium Pctronnte, Neutral. 1 Busty. Tetra-(2-ethylhexandinl-i,3) 1 Slight Rust. Isopropoxy Steuroxy lolysilicate 1 NJ Rust.

According to the test instructions, only the part of the sample below the surface of the oil i to be inspected for rust. The data in Table V are based on that statement. It should be noted that the sample above the surface of the oil showed heavy rusting in the cases where the barium petronate compounds were used, and no rusting wa observed above the surface of the oil on those specimens which were immersed in oil containing the surfactants. The observations mean that the compounds of the invention give vapor-phase corrosion protection as well as solution corrosion protection of the steel. This fact is important, since those ferrous metals parts in engines not coated with an inhibited oil are subject to rusting and an inhibited oil containing a barium sulfonate would offer no protection to these unprotected parts. Oil containing the compounds of the invention which possess vapor-phase corrosion protection protects these unprotected parts as well as the oil-coated metal surfaces.

To show that oils modified by the addition of the com pounds of the invention possess anti-oxidant properties, they were subjected to a test entitled Oxidation Charactcristics of Inhibited Steam Turbine Oils (A.S.T.M. designation D943-54). This test determines the life of the oxidation inhibitor in oil in the presence of iron and copper at elevated temperatures. The acid number of the oil is determined at the end of the test, and is used as a measure of the effectiveness and life of the oxidation inhibitor.

In the series of tests the silicon acylates and methanolamine silicates herein described were employed as oxidation inhibitors along with two commercial oxidation inhibitors basic and neutral barium petronate. A copper corrosion inhibitor was also added to prevent the compounds from attacking the copper. The results of these tests shown in Table VI indicates that our surfactants possess oxidation inhibting characteristics at! east as great as the two commercial oxidation inhibitors.

The pour point of a petroleum oil or the lowest tem perature at which the oil will pour or flow when it is chilled under prescribed conditions was determined for oils modified with the additives of the invention. The test entitled, Cloud and Pour Points" (A.S.T.M. Desig nation 097-47), was run by placing a 2" height of oil in a standard test jar. The jar i stoppered with a cork carrying a thermometer. The thermometer bulb is placed is" below the surface of the oil. Beginning with a temperature 20 F. before the expected pour point, at each test thermometer reading that is a multiple of 5 F., the test jar is removed from the coolant and tilted just enough to ascertain Whether there is a movement of the oil in the test jar. If movement of the oil is observed, the test jar containing the oil is placed in a colder coolant media, and the process is repeated until no movement is observed upon tilting the jar. When the oil shows no movement on tilting, it is held in a horizontal position for 5 seconds; if no movement of the oil occurs, the pour point is taken as the temperature 5 F. above this solid point.

A standard A.S.T.M. pour point testing apparatus was used in tests. A dewaxed solvent (S.A.E. 300) was used in order to prevent interference of the cloud point with the pour point determinations. The results of the pour point test are shown in Table VII.

l S.A.E. 300, solvent dewascd oil.

The data in Table VII show that the compounds of the invention possess pour point depressant properties. Using a Falex load tester, the load carrying capacity of oils modified by the addition of the additivies of the invention was determined.

The results of these tests are indicated in Table VIII.

TABLE VIII Additive in Gulf Falex test Security Oil A: scale load in pounds None 600 1% butoxy stearoxy polystannate 1500 1% hydroxy stearoxy polytitanate 900 This application is a continuation-in-part or our copending application, Serial No. 643,934, filed March 5, 1957, now abandoned and entitled Lubricating Oil Additives.

What is claimed is:

l. A lubricating composition consisting essentiaily of a mineral oil of lubricating viscosity selected from the group consisting of petroleum lubricating oils and petroleum 7 engine oils, and containing as a corrosion inhibitor, pour point depressant, and dispersant between 0.1 and 5 weight percent of at least one compound selected from the group consisting of the acylates having the formula:

wherein M is selected from the group consisting of silicon, tin, and lead; R is a short chain alkyl group having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; and x is a small number up to about 10; the aminoalcohol derivatives having the formula:

wherein R is a short chain alkyl group having up to 10 carbon atoms; Q is selected from the group consisting of tin, lead, zirconium, and silicon; R is selected from the group consisting of hydrogen and short chain alkyl and hydroxyalkyl groups having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; y is a member from to 3; and z is a number from 2 to and p is a number having a maximum value of 4-y; and the polyhydric alcohol derivatives having the formula:

wherein Q is selected from the group consisting of tin, lead, zirconium, and silicon; R is a short chain alkyl group having up to carbon atoms; Z is a short chain acyclic polyvalent saturated hydrocarbon radical having up to 10 carbon atoms; y is a number from 0 to 3; and v is a number from 1 to 3.

2. A lubricating composition consisting essentially of a mineral oil of lubricating viscosity selected from the group consisting of petroleum lubricating oils and petroleum engine oils, and containing as a corrosion inhibitor, pour point depressant, and dispersant between 0.1 and 5 weight percent of at least one compound having the formula:

(mo-R Ho- -llI-O -Ir OR x wherein M is selected from the group consisting of silicon, tin, and lead, R is a short chain alkyl group having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; and x is a small whole number up to about 10.

3. The lubricating composition defined in claim 2 wherein .r is from 1 to 5.

4. The lubricating composition defined in claim 2 wherein R contains up to 4 carbon atoms and R contains up to 17 carbon atoms.

5. A lubricating composition consisting essentially of a mineral oil of lubricating viscosity selected from the group consisting of petroleum lubricating oils and petroleum engine oils, and containing as a corrosion inhibitor, pour point depressant, and dispersant from 0.1 to 5 weight percent of at least one compound having the formula:

wherein R is a short chain alkyl group having up to 10 carbon atoms; Q is selected from the group consisting of tin, lead, silicon, and zirconium; R is selected from the group consisting of hydrogen and short chain alkyl and hydroxyalkyl groups having up to 10 carbon atoms; R is a long chain alkyl group having from 10 to 19 carbon atoms; y is a number from 0 to 3; z is a number from 2 to 5 and p is a number having a maximum value of 4y.

6. The lubricating composition defined in claim 5 wherein R and R contain up to 4 carbon atoms and R contains up to 17 carbon atoms.

7. The lubricating composition defined in claim 5 wherein p is at least 1.

8. A lubricating composition consisting essentially of a mineral oil of lubricating viscosity selected from the group consisting of petroleum lubricating oils and petroleum engine oils, and containing as a corrosion inhibitor, pour point depressant, and dispersant from 0.1 to 5 weight percent of at least one compound having the formula:

a m orozt mvns wherein Q is selected from the group consisting of tin, lead, zirconium, and silicon; R is a short chain alkyl group having up to 10 carbon atoms; Z is a short chain acyclic polyv alent saturated hydrocarbon radical having up to 10 carbon atoms; y is a number from 0 to 3; and v is a number from 1 to 3.

9. The lubricating composition defined in claim 8 wherein R contains up to 4 carbon atoms and 2 contains up to 8 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,681,922 Balthis June 22, 1954 2,708,203 Haslam May 10, 1955 2,824,114 BoStWiCk Feb. 18, 1958 2,913,469 Russell Nov. 17, 1959 

1. A LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL OIL OF LUBRICATING VISCOSITY SELECTED FROM THE GROUP CONSISTING OF PETROLEUM LUBRICATING OILS AND PETROLEUM ENGINE OILS, AND CONTAINING AS A CORROSIN INHIBITOR, POUR POINT DEPRESSANT, AND DISPERSANT BETWEEN 0.1 AND 5 WEIGHT PERCENT OF A LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE ACYLATES HAVING THE FORMULA: 